Seismic Activity Drops, No Signs of Big Eruption by Bárðarbunga

Compared to previous nights, last night was rather quiet as far as seismic activity goes in the area around Bárðarbunga. The largest earthquake was of magnitude 4.1. Almost 400 quakes were picked up by sensors, most by the northern tip of the intrusive dyke. There were also some minor quakes near Askja volcano.

Four cauldrons, also known as lows or calderas, were seen in the glacier east-southeast of Bárðarbunga during an observation flight yesterday, indicating melt caused by great geothermal activity or possibly a sub-glacial eruption.

Geophysicist Magnús Tumi Guðmundsson told ruv.is this morning that a significant amount of ice has melted, yet earthquake monitors show no signs of a big eruption.

“Around 30-40 million cubic meters [1,1-1,4 billion cubic feet] of water have flowed from under there but we don’t know whether this has been happening in the past days or just today [yesterday]. However, by what we can see on earthquake monitors there are no indications of a great volcanic eruption taking place,” Magnús stated.

“We don’t know what has happened with this water, whether it is flowing somewhere now or whether it has flowed down to Grímsvötn. We will have to find out once further observations have been made, he concluded.

Previously, a large glacial flood in the river Jökulsá á Fjöllum north of Vatnajökull was feared in case of a volcanic eruption in Bárðarbunga, but now it is believed that the melt water may also accumulate in glacial lakes Grímsvötn and burst forth as a flood south of the glacier, as occurred during the 1996 Gjálp eruption.